1. Field of the Invention
The present invention relates to a piezoceramic device and a method for manufacturing the same, and more particularly, to a piezoceramic transducer (PZT transducer) and a method for manufacturing the same.
2. Description of the Related Art
In prior art, a PZT transducer is applicable to an atomizing humidifier, and is capable of generating ultrasonic waves in water to raise a water column, so that Rayleigh wave liquid droplets of surface acoustic waves are sprayed at an interface of the water column and the air and blown into the air by a fan, thereby transporting mist droplets into the ambient environment to achieve the purpose of increasing the humidity of the environment. The size of the liquid droplet depends on the ultrasonic frequency; the higher the frequency, the smaller the liquid droplet, and the smaller the mist amount in the liquid droplet transporting device.
Some conventional atomizing humidifiers spray out small liquid droplets of drug with ultrasonic waves which are inhaled into the lungs through the nose, so as to treat diseases (such as asthma). Some conventional atomizing humidifiers spray out liquid droplets of detergent with ultrasonic waves which permeate and are distributed on dishes, so as to remove grease with a small amount of water, thereby achieving a water-saving function of the dishwasher. In addition to generating water droplets, some conventional atomizing humidifiers generate ozone through high-voltage point discharge; the ozone floats in the air with the water droplets, and then is inhaled by human body to achieve the health-enhancing effect of antioxidant.
Prior-art design of the atomizing humidifier focuses on how to generate a large amount of water droplets (referred to as mist amount) with a low input of electric energy, and the design emphasis is on the liquid droplet transporting device, the power supply, and the vibration circuit. As the water amount in the spray water tank gradually decreases, the transducer still performs ultrasonic vibration; since ultrasonic energy cannot be transported without water, the transducer will become excessively hot due to energy accumulation and malfunction when the temperature exceeds the Curie temperature. In order to prevent such situation, the design focuses on detection of storage water level and automatic control of water input from a large water tank to the spray water tank by maintaining a certain distance between the vibration plane of the transducer and the liquid level, controlling the angle of inclination of the transducer to the liquid level, or adding a duct to remove large liquid droplets, so as to obtain a large or stable spray amount.
In recent years, the demand for light, thin, small, and portable atomizing humidifiers has increased, and small-power spraying devices have gradually become the trend. In the design, a piezoceramic plate is used to generate vibration to extrude the liquid to pass through a metal sheet with small holes to generate mist droplets. The design of atomizing humidifier construction is adopted in most cases, but few discussions on how to manufacture a PZT transducer having a large spray amount and a long service life exist in documents and patents.
Several prior art documents about atomizing humidifier transducers are listed and described briefly below.
Prior art document 1: “Ultrasonic Transducer” by Takahashi Minoru; “Application of Piezoceramics” edited by Okazaki Kiyoi, Ichinose Noboru, Igarashi Syuji, Ono Ryuji, and Yamamoto Hirotaka, and published by Gakkensya, pp. 184-191 (1988).
Some qualitative and theoretical explanations of manufacturing of the atomizing humidifier transducer are set forth, but the effects of electrode design and adhesion process of the transducer on the mist amount are not disclosed.
Prior art document 2: U.S. Pat. No. 4,257,989A (TDK atomizing humidifier)
Structure combination of an atomizing humidifier and electrode arrangement of a transducer are disclosed, but the relevant manufacturing method and performance of the transducer are not disclosed.
Prior art document 3: U.S. Pat. No. 5,021,701A (TDK transducer erecting transducer)
Electrode arrangement of a transducer is disclosed, but the relevant manufacturing method and performance of the transducer are not illustrated.
Prior art document 4: U.S. Pat. No. 4,976,259 (Medical Ultrasonic Nebulizer)
A nebulizer is disclosed, which uses a transducer with the same electrode arrangement, but how to obtain a large mist amount is not illustrated.
Prior art document 5: U.S. Pat. No. 5,757,104 (Optimal matching method of transducer and circuit).
An optimal matching method of a transducer and a circuit is disclosed, in which the transducer with the same electrode arrangement or different electrode arrangements is capable of matching an optical vibration circuit to obtain the maximal vibration, but how to obtain the maximal vibration (mist amount) through a ratio of the electrode diameter of the transducer to the diameter of the ceramic plate is not illustrated.
Therefore, it is necessary to provide an innovative and inventive PZT transducer and a method for manufacturing the same.